Storing the system clock frequency in struct octeon_spi avoids
calling the MIPS specific octeon_get_io_clock_rate() for every transfer.
Signed-off-by: NJan Glauber <jglauber@cavium.com>
Tested-by: NSteven J. Hill <steven.hill@cavium.com>
Signed-off-by: NMark Brown <broonie@kernel.org>